apache

Anybody running without the fan shroud? At what speed does the air flow reduce enough to be a problem ,If im traveling at 40 on a 100 degree day will it make a difference. Today I serviced the cooling system including a cummins thermostat, Flushed the system, rad looked good inside. now it runs at a stable temp just above the 1/4 up mark, but still will climb up to 1/2 or a little more climbing a 7% 4 mile long grade pedaled at 65 mph in o/d,Max boost is 16 psi . The temp was 55 today and rainy. this bothers me, I dont know if the guage is screwy or? My other 93 will rarely move in temp unless its 110 out, pedaled at 80 mph in o/d. There is a difference of the dually has no extra trans cooler under the bed and again is missing the fan shroud. Could these things make that much difference? any suggestions? besides install a good temp guage . What is a safe max temp to run at. in a CTD?

Alec

Over 40 mph the shroud should make very little difference. I would bet that the big difference is the oil cooler for the transmission.

chaikwa

I kind of have the same preoblem with my 93 4X4 dually. When it's cold out, say below 25F, I can't get it to make any temp in the 'normal' range of the guage. But when it's over 40F outside, it will climb to the half way mark or higher if I work the truck in any way, even climbing a hill with no load. It used to run just above the 1/4 mark all the time. I still have mt shroud and I flushed the cooling system twice. I'm beginning to think maybe the thermostat is stuck halfway open and not moving.

chaikwa.

Redleg

If the guys will back me on this, I'm pretty sure the thermostat is designed not to go bad while closed, or at least allow fluid to be able to pass through if closed. So you may need to change it. It's not a tuff job to do.

apache

For all the early first gens there was a warning notice and a template with the new Cummins thermostat. Cummins says on some earlys you will need to use a diegrinder or? to enlarge the hole in the block or the thermostst will hang up. I wonder if other aftermarket suppliers will have this with the thermostat. Pays to get good stuff. My Cummins thermo was $26.00. Well worth it.

chaikwa

Thank you Redleg and apache, I'll give a new thermostat a try. A Dodge dealer should have a Cummins thermostat, correct?

apache

I dont know. I deal with a truck repair shop for parts. or any cummins shop. also there is a updated # for the thermo. Just go to the search and look for part #s. It sure stoped the cycling of my temps.

Redleg

Yes Cummins has them, just call ahead to ensure it's in stock, and take the old one with you to compare the fit.